I have a board that demostrates this very nicely. As soon as I get my
scope/extraction system working again I will publish some results. The
board is two layers with ground on one side and 50 Ohm traces on the other.
Yes, these traces are quite wide, on the order of 0.100". There are several
right angel bends with square corners. The corners are quite visible.

I don't know what kind of TDR or fixturing you might have used, but the
excess capacitance is very real and can be seen. It is also illustrated in
a number of microwave books. If your fixturing caused a significant loss (>
100 ps) of risetime of the step out of the TDR, then the capacitance effect
will be washed out.

Sincerely,

ed sayre
==========================
At 08:36 AM 5/10/01 -0700, Ritchey Lee wrote:
>Any of you who want to know how the myth about right angle bends got
>started, look
>at figure 7.17 on page 155. This alleges that right angle bends can be
>seen by a
>TDR. I've done this measurement dozens of times and coiuld never see a
right
>angle bend.
>
>A few years ago, I called Mr. Blood the author of the book and asked
>about the
>diagram. His reply was that he knew the diagram was flawed, but there
>wasn't time
>to fix it before the book went to press.
>
>As a result, thousands of engineers have spend countless time worrying
>about right
>angle bends.
>
>When we publish technical information such as this, it is important to
>insure it
>is accurate.
>This applies especially to applications notes, whic often contain entirely
>false
>data.
>
>Lee
>
>Rich Peyton wrote:
>
> > FYI,
> >
> > The hard copy can be ordered free of charge.
> >
> > Rich
> >
> > Roehrner Wolfgang wrote:
> >
> > > http://www.onsemi.com/home <http://www.onsemi.com/home>
> > >
> > > In the Menu-tree go to:
> > >
> > > Technical Documents
> > > CD/Document Ordering
> > > General Search
> > >
> > > search for document number: hb205
> > > download it as pdf (or order!).
> > >
> > > regards,
> > > Wolfgang
> > >
> > > -----Original Message-----
> > > From: Ashok Babu K [mailto:k.ashokbabu@gdatech.co.in]
> > > Sent: Tuesday, April 10, 2001 12:39 PM
> > > To: si-list@silab.eng.sun.com> > > Subject: [SI-LIST] : MECL System Design Handbook
> > >
> > > Hi all,
> > > I see that a good resource for general high speed termination design
and
> > > especially ECL/PECL termination is Motorola's MECL System Design
> Handbook by
> > > Blood Jr., and William R. Many articles and papers specify the same as
a
> > > good resource. Unfortunately I could not get the soft copy of the MECL
> > > System Design Handbook. I could not get it from the ON Semiconductor
> > > website. If any of you have the PDF file of the same or know where it
> can be
> > > obtained, please inform me. Any suggestions of other resources are
highly
> > > welcome.
> > > Regards,
> > > Ashok.
> > >
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